20 13 great wall c30 engine sounds like a pickup truck when idling, just like a diesel pickup truck. What happened?

20 13 great wall c30 engine sounds like a pickup truck when idling, just like a diesel pickup truck. Engine vibration usually has several reasons. The most common reason for the serious carbon deposition in the engine is that the throttle valve is too dirty or the fuel injector has too much carbon deposition, because the gasoline adsorbed on the carbon deposition after landing is sucked into the cylinder for combustion by the engine, and the combustible mixture of the engine is sometimes rare and sometimes thick, resulting in idling vibration after cold start. Solution: The company cleans the oil circuit, and checks whether the idle motor has carbon deposit, so it should be cleaned.